How old are your kids? If they're used to acting to avoid a punishment, a sudden change from you (from being a stern "do it or else" mom, to "how can I help you") could absolutely cause problems, as they aren't likely to take you seriously.
My advice would be to not stop doing whatever you were doing before deciding to try UP, but to read the book anyway (if you're still interested in learning more about UP, that is) and slowly work your way into the type of parent you want to be.
UP (in my experience) is ALL about listening to your kids, and acting towards their needs (rather than punishing the behavior). It can certainly take some time to learn how to do this, but if you're truly interested in UP, don't sell yourself short. There's a big learning curve there, if it doesn't immediately come naturally to you. It will come.
And speaking of books, one of the best books that helped me is called "The Science of Parenting". It doesn't talk about one specific parenting technique, but it compares different techniques and explains (often with pictures of MRI's, or diagrams) how these affect a child's brain development. When certain actions are appropriate (like the use of time out, daycare, sleep training vs co-sleeping), things like that. It might give you a better insight on how you want to handle certain situations, rather than what type of parenting style you want to follow.
With that in mind though, definitely read UP when you're in a better frame of mind. It sounds like the "sick and tired" is getting the better of you. Maybe even take some time to sit down with your kids (think age appropriate and get to their levels!) and flat out talk to them about how they want to be treated (and why).
I'm really sorry to hear that you're feeling so low right now. But hang in there!! Take some deep breaths, and take it all one day at a time.
